Solubility of CO2 in Ethyl Lactate and Modeling of the Phase Behavior of the CO2 + Ethyl Lactate Mixture

Ethyl lactate (ethyl 2-hydroxypropanoate) is emerging as an ecofriendly solvent with wide applications in the food, pharmaceutical, and fine chemical industries. Furthermore, its potential use as a solvent in chemical reactions which could be performed in supercritical media and as an effective cosolvent in supercritical extraction processes and/or in antisolvent precipitation processes has also been studied. In view of this, knowledge of the phase behavior of ethyl lactate + CO2 binary is vital for the modeling and design of such processes. In this work, data on the solubility of CO2 in the ethyl lactate rich liquid phase at T = (311, 318, and 323) K and pressures ranging from (1 to 8.1) MPa is reported for the first time. The compositions of the liquid phase were measured using a variable volume view equilibrium cell. The new data measured together with previously reported data on the solubility of ethyl lactate in CO2 were employed to explore the capabilities of two different thermodynamic models, namely, the cubic Soave-Redlich-Kwong equation of state (SRK-EoS) and the group contribution EoS (GC-EoS), to represent the phase equilibria of the binary ethyl lactate + CO2 mixture.